Neuromorpha vorax : a previously unculturable cosmopolitan protist with an unexpectedly complex life-cycle belonging to Glissomonadida Clade-U/Group-TE

Soil protists are increasingly recognized as common members of complex communities that associate with plant root systems, though their contributions to these communities and to the plant host remain obscure. Members Clade-U/Group-TE, are cosmopolitan soil protists and are often among the most abundant protists associated with plant roots. Here we describe the isolation, culturing and characterization of Neuromorpha vorax , a member of the previously uncultured Clade-U/Group-TE branch of the order Glissomonadida. N. vorax grew readily when provided bacteriophage lysate as a food source. This allowed us to grow large numbers of the organisms from single-cell isolates and provided ideal conditions for following transitions from one morphology to another. N. vorax , like most Glissomonads, has a small, flagellated gliding form, but it also displays a wide range of other morphologies including: a crawling form; small and large trophozoites with multiple, long filopodia; small and large resting cysts; clusters of large dividing cells and it displayed cannibalistic feeding behaviors. Given the small size of most Glissomonads, it may be that other members of this important group, known from environmental surveys, but currently uncultured, might also be readily grown on bacteriophage lysates. In addition, given an abundant food source and clear viewing by microscopy, Glissomonads and other small protists may be found to have life cycles and behaviors that are more complex than is currently appreciated.